To get Perf data you need to collect that from the agent, typically by going to:
https://learn.microsoft.com/en-us/azure/azure-monitor/agents/data-sources-performance-counters
or by enabling VM insights.
https://learn.microsoft.com/en-us/azure/azure-monitor/vm/vminsights-overview
This is data you wouldn't typically put in the same Workspace as Azure Sentinel for cost reasons.